Bifurcation catheter assembly and methods

ABSTRACT

A catheter assembly includes a main catheter branch and a side catheter branch. The main catheter branch includes a main balloon, a side balloon and a side inflation member. The side inflation member intersects the side balloon at a location on the side balloon that is offset laterally from a central line passing from a distal most point on the side balloon to a proximal most point on the side balloon. The side balloon is configured to extend radially outward relative to the main balloon when the side balloon is inflated. The side catheter branch can be centrally aligned with the side balloon central line and be positioned laterally adjacent to the side inflation lumen.

RELATED APPLICATIONS

This application is a continuation of co-pending U.S. application Ser.No. 12/183,162, filed Aug. 31, 2008, the entire disclosure of which isincorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to catheter systems and methods for treatingvessel bifurcations. Preferred arrangements relate to inflation lumenand balloon configurations for bifurcation catheter systems.

BACKGROUND

Catheters are used with stents and inflatable structures to treatconditions such as strictures, stenoses, and narrowing in various partsof the body. Various catheter designs have been developed for thedilatation of stenoses and to deliver and deploy stents at treatmentsites within the body.

Stents are typically intraluminally placed by a catheter within a vein,artery, or other tubular shaped body organ for treating conditions suchas, for example, occlusions, stenoses, aneurysms, dissections, orweakened, diseased, or abnormally dilated vessels or vessel walls, byexpanding the vessels or by reinforcing the vessel walls. Oncedelivered, the stents can be expanded using one or more inflatablemembers such as balloons. Stents can improve angioplasty results bypreventing elastic recoil and remodeling of the vessel wall and treatingdissections in blood vessel walls caused by balloon angioplasty ofcoronary arteries. Stents can also be used as a drug delivery medium fortreatment of damaged portions of a vessel.

While conventional stent technology is relatively well developed, stenttechnologies related to treatment of the region of a vessel bifurcationare still being developed.

SUMMARY OF THE DISCLOSURE

The present disclosure relates generally to catheter assemblies fortreatment of bifurcated lumens in a patient, such as vesselbifurcations. In one example, a catheter assembly includes a maincatheter branch and a side catheter branch. The main catheter branchincludes a main balloon, a side balloon and a side inflation member. Theside inflation member intersects the side balloon at a location on theside balloon that is offset laterally from a central line passing from adistal-most point on the side balloon to a proximal-most point on theside balloon. The side balloon is configured to extend radially outwardrelative to the main balloon when the side balloon is inflated. The sidecatheter branch can be centrally aligned with the side balloon centralline and be positioned laterally adjacent to the side inflation lumen.

The side inflation lumen can include a proximal segment that extendsproximally from the side balloon, and a distal segment that extendsdistally from the side balloon. Typically, at least the proximal segmentintersects the side balloon laterally offset from the side ballooncentral line. In some arrangements, the distal segment can alsointersect the side balloon at a laterally offset location from the sideballoon central line.

The catheter assemblies can be used to deliver a stent to a vesseltreatment site. An example stent delivered by the catheter assembliesincludes a lateral branch opening through which the side catheter branchextends. The side balloon is aligned with the lateral branch opening,wherein inflation of the side balloon can help further open the lateralbranch opening of the stent.

There is no requirement that an arrangement or method include allfeatures characterized herein to obtain some advantage according to thisdisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of an exemplary catheter assemblyfor treatment of a bifurcation, the assembly constructed having aproximal end portion and distal end portion, wherein the distal endportion includes main and side balloons and main and side catheterbranches.

FIG. 2 is a schematic side view of the distal end portion of thecatheter assembly shown in FIG. 1 with the balloons in the un-inflatedstate.

FIG. 3 is a schematic side view of the distal end portion of thecatheter assembly shown in FIG. 1 with the balloon portions inflated andthe stent expanded.

FIG. 4 is a schematic cross-sectional view taken along cross-sectionalindicators 4-4 in FIG. 2.

FIG. 5 is a schematic cross-sectional view of the catheter assemblyshown in FIG. 3.

FIG. 6 is a schematic top view of the catheter assembly shown in FIG. 3with the stent removed.

FIG. 7 is a schematic is a schematic cross-sectional view taken alongcross-sectional indicators 7-7 in FIG. 5.

FIG. 8 is a schematic top view of an example side balloon with an offsetside inflation member segment.

FIG. 9 is a schematic top view of another example side balloon with twooffset side inflation member segments.

FIG. 10 is a schematic top view of another side balloon and analternative arrangement of two side offset inflation member segments.

FIG. 11 is a schematic rear view of an example side balloon with a sideinflation member segment centrally positioned.

FIG. 12 is a schematic rear view of an example side balloon with anoffset side inflation member segment.

FIG. 13 is a schematic front view of an example side balloon with anoffset side inflation member segment.

FIG. 14 is a schematic top view of the side balloon and side inflationmember segments shown in FIG. 8 with a centrally oriented side catheterbranch.

FIG. 15 is a schematic top view of the side balloon and side inflationmember arrangement shown in FIG. 9 with a centrally oriented sidecatheter branch.

FIG. 16 is a schematic top view of the side balloon and side inflationmember arrangement shown in FIG. 10 with a centrally located sidecatheter branch.

FIG. 17 is a schematic rear view of the side balloon and side inflationmember shown in FIG. 28 with an offset side catheter branch.

FIG. 18 is a schematic rear view of the side balloon and side inflationmember arrangement shown in FIG. 15 with a centrally located sidecatheter branch.

FIG. 19 is a schematic front view of the side balloon and side inflationmember arrangement shown in FIG. 15 with a centrally located sidecatheter branch.

FIG. 20 is a schematic cross-sectional side view of an example two-piecemold used to generate a side balloon from a side inflation member.

FIG. 21 is a schematic cross-sectional top view of the mold shown inFIG. 20.

FIG. 22 is a schematic top view of an example side balloon with offsetside inflation member segments and a centrally oriented side catheterbranch, wherein the side balloon includes an angled surface.

FIG. 23 is a schematic side view of the side balloon, side inflationmember, and side catheter branch shown in FIG. 22.

FIGS. 24-26 illustrate the catheter assembly shown in FIGS. 1-7 in usetreating a vessel bifurcation.

FIG. 27 illustrates the catheter assembly having a proximal sideinflation member segment that is centrally located on a rear side of theside balloon.

FIG. 28 illustrates the catheter assembly shown in FIG. 27 with the mainand side balloons inflated.

FIG. 29 is a schematic cross-sectional view taken along cross-sectionalindicators 29-29 in FIG. 27.

FIG. 30 is a schematic cross-sectional view taken along cross-sectionalindicators 30-30 in FIG. 28.

FIG. 31 is a schematic top view of the catheter assembly shown in FIG.27 with the stent removed.

FIG. 32 is a schematic top view of the catheter assembly shown in FIG.28 with the stent removed.

DETAILED DESCRIPTION

This disclosure relates to bifurcation treatment systems, catheterassemblies, and related methods of treating bifurcations in a patient'sbody. The term bifurcation means a division location from one unit intotwo or more units. Generally, two types of bifurcations of a body organinclude: 1) a main tubular member defining a main lumen and a branchtubular member defining a branch lumen that extends or branches off fromthe main tubular member, wherein the main and branch lumens are in fluidcommunication with each other, and 2) a primary or main member defininga primary or main lumen (also referred to as a parent lumen) that splitsinto first and second branch members defining first and second branchlumens. The term lumen means the cavity or bore of a tubular structuresuch as a tubular organ (e.g., a blood vessel).

An example bifurcation is a vessel bifurcation that includes acontinuous main vessel and a branch vessel, wherein the vessels define amain lumen and a branch lumen, respectively that are in fluidcommunication with each other. Alternatively, a vessel bifurcation caninclude a parent vessel that divides into first and second branchvessels, wherein the vessels define a parent lumen and first and secondbranch lumens, respectively, which lumens are all in fluid communicationwith each other.

Example applications of the inventive principles disclosed hereininclude cardiac, coronary, renal, peripheral vascular, gastrointestinal,pulmonary, urinary, and neurovascular systems. The catheter assemblies,systems and methods disclosed herein to can be used for locating abranch vessel of the vessel bifurcation and for placement of a stentrelative to the vessel bifurcation for treatment of the vesselbifurcation.

While alternatives are possible, the example catheter assembliesdisclosed herein generally include at a distal end portion thereof amain catheter branch and a side catheter branch. The side catheterbranch typically includes a side guidewire housing that defines a sideguidewire lumen. A distal end portion of the side catheter branch isconfigured to extend into a branch vessel at a vessel bifurcation. Theside catheter branch is used to align features of a stent carried by theproximal end portion of the vessel bifurcation treatment system with anostium (also referred to as a branch vessel opening) into the branchvessel.

The main catheter branch includes a catheter shaft having a distal endportion. A main balloon and a side balloon are positioned at the distalend portion of the catheter shaft. A main catheter branch includes amain guidewire housing that defines a main guidewire lumen. The mainguidewire housing extends through the main balloon. The side balloon ispositioned on a side inflation member. The side inflation member canextend in parallel with a longitudinal dimension of the main balloon.The side inflation member defines a side inflation lumen. The sideinflation member can include proximal and distal segments that areconnected in fluid communication with the side balloon. One aspect ofthe present disclosure relates to the intersection point between theside inflation member and the side balloon. The side inflation membercan intersect the side balloon at a location that is laterally offsetfrom a central proximal-distal line of the side balloon. The centralproximal-distal line of the side balloon extends from a proximal-mostpoint on the side balloon to a distal-most point on the side balloon.Typically, the central proximal-distal line of the side balloon is alsolocated centrally between opposing laterally offset sides of the sideballoon (e.g., sides 61-63 in FIGS. 8-10). The location of the centralproximal-distal line can also be defined as the line that divides theside balloon in half in a projection view of the side balloon, whereinthe projection view is that view from a direction in which the sideballoon extends radially outward from the main balloon (e.g., see FIGS.8-10).

Another aspect of the present disclosure relates to variousconfigurations of the side balloon (e.g., shape and size) and theinterface between the side balloon and the side catheter branch when theside balloon is inflated.

Referring now to FIGS. 27-31, an example catheter assembly 200 is shownand described. The catheter assembly 200 includes a main catheter branch12, a side catheter branch 14, and a stent 16. The main catheter branch12 includes a catheter shaft 30 having a distal end portion 42, aguidewire housing 32, a main balloon 36, a side inflation member 34, anda side balloon 38. The side catheter branch 14 has a distal end portion70. The stent 16 is operably mounted to the main balloon 36, sideinflation member 34, and the side catheter branch 14 using, for example,crimping techniques. The distal end portion 70 of the side catheterbranch 14 extends into the stent 16 through a proximal end 82 thereof,and protrudes out of a lateral branch opening 84. The lateral branchopening is positioned on the stent at a location between the proximaland distal open ends 82, 80.

The catheter assembly has a first distal profile P1 at a location distalthe lateral branch opening 84, and a second distal profile P2 at alocation proximal of the lateral branch opening 84 and distal of theproximal end 82 of the stent. As shown in FIG. 29, the profile P2results from stacking the proximal segment of the side inflation memberon top of the main balloon, and stacking the side catheter branch 14 ontop of the side inflation member 34. Such stacking of the side inflationmember 34 and the side catheter branch 14 helps maintain the sidecatheter branch 14 centrally aligned with a central proximal-distal lineA of the side balloon 38 (see FIG. 32). The profiles P1, P2 cangenerally be the same, wherein a difference between P1 and P2 being thatthe side catheter branch is positioned outside of the stent for theprofile P1 versus inside the stent for the profile P2. In one example,the profiles P1, P2 are each in the range of about 0.055 in. to about0.062 in., inclusive.

When the main and branch balloons 36, 38 are inflated, the side catheterbranch 14 typically moves laterally into a position from on top of theproximal segment of the side inflation member to a position laterallyadjacent to the proximal segment of the side inflation member 34 asshown in FIG. 30. This lateral shifting of the side catheter branchresults in the side catheter branch not being aligned centrally with thecentral proximal-distal line A of the side balloon 38 as shown in FIG.32. FIG. 31 illustrates how the side catheter branch 14 is aligned withthe side inflation member 34 and side balloon 36 along the centralproximal-distal line A prior to inflation of the main and side balloons36, 38. FIG. 32 illustrates how the side catheter branch 14 is shiftedlaterally (laterally to the right in this arrangement) relative to thecentral proximal-distal line A of the side balloon 38.

When the side catheter branch 14 shifts laterally in this manner, theside catheter branch 14 typically is offset from being centrally alignedwith the lateral branch opening 84 of the stent 16 as shown in FIG. 30.Typically, the side catheter branch 14 shifts around to a right or leftside of the side balloon 38, which results in the side catheter branch14 extending out of the lateral branch opening 84 along the left orright side of the lateral branch opening 84. A side catheter branch thatis not aligned centrally with the lateral branch opening of the stentcan affect proper alignment of the lateral branch opening 86 with anopening into a branch vessel of a vessel bifurcation as will bediscussed in further detail below with reference to FIGS. 24-26.

Referring now to FIG. 11, an example side balloon 38 is shown from arear or proximal view. The proximal segment of the side inflation member34 is positioned at a center location at a portion across the width ofthe side balloon 38 along the proximal side 62. When the side balloon 38and side inflation lumen 34 are used with a side catheter branch 14 asdescribed above with reference to FIGS. 27-32, the side catheter branch14 tends to shift laterally as shown in FIG. 17 so as to be positionedlaterally adjacent to the proximal segment 50 of the side inflationmember 34 at a location proximal of the side balloon 38. FIG. 17illustrates the side catheter branch 14 positioned to the right of theside inflation member 34 such that the distal end portion 70 of the sidecatheter branch 14 extends along the right side 63 and across theradially outward facing surface 64 of the side balloon 38 when the sideballoon 38 is inflated. In other instances, the side catheter branch 14shifts laterally to the left so as to be aligned along the left side 61of the side balloon 38.

Other example catheter assemblies disclosed herein with reference toFIGS. 1-26 include various configurations for attachment of the sideinflation member distal and proximal segments to the side balloon. Thesearrangements can improve alignment of the side catheter branch 14centrally with the central proximal-distal line of the side balloon whenthe side and main balloons are inflated. By maintaining properorientation of the side catheter branch relative to the side balloon,the catheter assemblies disclosed herein can provide improvedconsistency in aligning the lateral branch opening of the stent with theostium of the branch vessel when treating a vessel bifurcation.

An example catheter assembly 10 is shown schematically with reference toFIGS. 1-7. The catheter assembly 10 is configured for treatment of avessel bifurcation such as the vessel bifurcation 22 shown in FIGS.24-26. While alternatives are possible, the catheter assembly 10generally includes a main catheter branch 12, a side catheter branch 14,and a stent 16. The main catheter branch 12 includes a catheter shaft 30having a proximal end portion 40 (see FIG. 1) and a distal end portion42. The catheter shaft 30 defines an inflation lumen 44 (see FIG. 7)that extends from the proximal end portion 40 to the distal end portion42.

The main catheter branch 12 further includes a main guidewire housing 32having a distal end portion 48. The main guidewire housing 32 defines amain guidewire lumen 46 as shown in FIG. 7 that is sized to advance overa main guidewire. The main guidewire housing 32 can extend within thecatheter shaft 30 between the proximal and distal end portions 40, 42.Alternatively, the main guidewire housing 32 can be configured as arapid exchange arrangement wherein the main guidewire housing extendsalong only a portion of the length of the catheter shaft 30.

The main catheter branch can also include a main balloon 36 extendingalong the distal end portion 48 of the guidewire housing 32. A proximalend of the main balloon 36 extends from the proximal end portion of thecatheter shaft 30, and a distal end of the main balloon 36 is secured tothe main guidewire housing 32 at the distal end portion 48 (see FIG. 7).

The main catheter branch 12 further includes a side inflation member 34.The side inflation member 34 includes a proximal segment 50 havingproximal and distal ends 51, 53, and a distal segment 52 having proximaland distal ends 55, 57 (see FIG. 7). The side inflation member defines aside inflation lumen 54 through which inflation fluid is provided to aside balloon 38. The side balloon includes distal and proximal sides 60,62, left and right sides 61, 63 (also referred to as opposing laterallyoffset sides), and a radially outward facing surface 64. Whenun-inflated, the side balloon 38 maintains a generally collapsed profile(e.g., see side balloon 38 in the collapsed state shown in FIGS. 27 and31). When inflated, the side balloon extends radially outward relativeto the side inflation member 34 and the main balloon 36 (see FIGS. 3, 5and 7). The side balloon 38 typically has a width W (see FIG. 6), alength L (see FIG. 6), and height H (see FIG. 7). The side balloon 38illustrated in FIGS. 1-26 has a generally cylindrical shape with acircular cross-section. In other examples, the side balloon can have avariety of different shapes, sizes and cross-sections.

The side balloon can extend from the side inflation member 34 and themain balloon 36 (i.e. a longitudinal axis or a longitudinal dimension ofthe side balloon and main balloon (e.g. axis B shown in FIG. 3)) at anangle different from the generally 90° (perpendicular) angle shown inthe Figures. While alternatives are possible, the side balloon 38 cangenerally extend from the side inflation member 34 and the main balloon36 at an angle in the range of about 30° to about 90°, inclusive.

FIGS. 1 and 2 illustrate the catheter assembly 10 with the main and sideballoons 36, 38 in an un-inflated state. FIG. 4 illustrates the catheterassembly 10 with the main and branch balloons 36, 38 in an inflatedstate. FIG. 4 illustrates the relative arrangement of the side inflationmember 34, side catheter branch 14, and main balloon 36 proximal of thelateral branch opening 84 in the stent 16. The side inflation member 34and side catheter branch 14 are positioned laterally adjacent to eachother and resting in contact with an outer surface of the balloon 36.

In the inflated state shown in FIGS. 3, 5, 6 and 7, the side inflationmember 34 is positioned offset laterally to the left relative to thecentral proximal-distal line A of the side balloon 38. The sideinflation member 34 can also be offset from a central plane C (see FIG.5) that extends through the central proximal-distal line A and alongitudinal axis B of the main balloon 36 (see FIG. 3). The offsetorientation of the side inflation member 34 provides space for the sidecatheter branch 14 to remain aligned with the central proximal-distalline A of the side balloon 38 as well as being centrally orientedrelative to the lateral branch opening 84 of the stent 16.

FIG. 6 illustrates a particular arrangement for connection of theproximal and distal segments 50, 52 of the side inflation member 34 tothe proximal and distal sides 62, 60 of the side balloon 38,respectively. The distal end 53 of the proximal segment 50 is connectedto the proximal side 62 of the side balloon at a position offset towardsthe left side 61 of the side balloon. The proximal end 55 of the distalsegment 52 is connected to the side balloon 38 along the distal side 60at an orientation offset laterally from the central proximal-distal lineA to the left side 61. This laterally offset arrangement of the proximaland distal segments 50, 52 relative to the central proximal-distal lineA of the side balloon 38 permits orientation of the side catheter branch14 along the central proximal-distal line A before and after inflationof the main and side balloons 36, 38. This arrangement typicallyprovides at least two possible advantages.

One possible advantage of intersecting the side inflation member 34 withthe side balloon 38 at a location laterally offset from the centralproximal-distal line A is that the profiles P3, P4 of the catheterassembly 10 in the un-inflated state shown in FIG. 2 can be reduced ascompared to an arrangement wherein the side catheter branch 14 isstacked on top of the side inflation member 34. Typically, the profilesP3, P4 (representing the maximum outer dimension of the catheterassembly along the stent 16 at locations distal and proximal of thelateral branch opening 84, respectively), are each less than theprofiles P1, P2 of the catheter assembly 200 described above. Thisreduced profile results from the ability to position the side catheterbranch 14 laterally adjacent to the side inflation member 34 in thecatheter assembly 10 instead of vertically on top of the side inflationmember 34 (see catheter assembly 200 in FIGS. 27-30).

Another possible advantage of intersecting the side inflation member 34with the side balloon 38 at a location laterally offset from the centralproximal-distal line A relates to maintaining alignment of the sidecatheter branch 14 along the central proximal-distal line A of the sideballoon 38 before, during and after inflation of the main and sideballoons 36, 38.

FIGS. 8-10 illustrate several connection arrangements of the distal andproximal segments of the side inflation member 34 to a side balloon 38.FIGS. 14-16 illustrate the arrangements of FIGS. 8-10 in combinationwith a side catheter branch 14 arranged along a central proximal-distalline A of the side balloon 38. FIGS. 8 and 14 illustrate intersection ofthe proximal segment 50 at its distal end 53 with the proximal side 62of the side balloon at a location offset laterally towards the rightside 63 of the side balloon. The distal segment 52 intersects at itsproximal end 55 with the distal side 60 of the side balloon and isaligned along the central proximal-distal line A of the side balloon 38.

FIGS. 9 and 15 illustrate the proximal segment 50 intersects at theproximal side 62 offset towards the right side 63 of the side balloon.The distal segment 52 intersects at the distal side 60 of the sideballoon offset to the left side 61 of the balloon. FIGS. 10 and 16illustrate the proximal and distal segments 50, 52 intersect with theproximal and distal sides 62, 60 of the side balloon and laterallyoffset towards the right side 63 of the side balloon 38.

The arrangement of FIGS. 8 and 14 can be modified in other examples tooffset the proximal segment 50 to the left side 61 rather than towardsthe right side 63 as shown. Likewise, in FIGS. 9 and 15 the proximalsegment 50 can be offset towards the left side 61 and the distal segment52 can be offset towards the right side 63 in other examples. The mirrorimage of the arrangement in FIGS. 10 and 16 is illustrated in FIG. 6.

FIGS. 12 and 13 illustrate the distal and proximal sides 60, 62 of theside balloon 38 and the various intersection points of the proximal anddistal segments 50, 52 at offset locations to the left or right sides61, 63 of the side balloon 38. FIGS. 18 and 19 illustrate thearrangements of FIGS. 12 and 13 and further illustrate positioning ofthe side catheter branch 14 centrally relative to the side balloon 38between the left and right sides 61, 63. In one example, the maximumwidth dimension of the proximal and distal segments 50, 52 of the sideinflation member 34 is substantially the same as the maximum widthdimension of the side catheter branch 14 in the area of the side balloon38. Therefore, offsetting the segments 50, 52 to either the left orright side relative to a position of the segments 50, 52 aligned withthe central proximal-distal line A a distance equal to half of thatmaximum width dimension will permit orientation of the side catheterbranch 14 along the central proximal-distal line A.

The maximum width W of the balloon 38 (see FIGS. 12 and 18) in oneexample can be about three times the maximum width dimension of the sidecatheter branch 14 or the side inflation member 34. With thesedimensions for the side balloon 38, the side catheter branch 14 canremain centrally aligned with the central proximal-distal line A and thesegments of the side inflation member 34 can be positioned on either theleft or the right side of the side catheter branch 14 without the sideinflation member 38 protruding laterally beyond the width of the sideballoon 38. In some preferred arrangements, the side inflation member 34does not extend laterally beyond the left or right side 61, 63 beyondthe width W of the side balloon 38. In other examples, the side ballooncan have any width W or other dimension that is unrelated to the maximumwidth dimensions of either the side catheter branch 14 or the sideinflation member 34.

Referring again to FIGS. 9 and 15, the intersection of the proximal anddistal segments 50, 52 at laterally offset orientations to the right orleft (or vice versa) of the central proximal-distal line A of sideballoon 38 can provide additional advantages when inflating the main andbranch balloons 36, 38. The catheter assembly 10 shown in FIGS. 1-7includes a side inflation member 34 that is connected at itsproximal-most and distal-most ends to the catheter shaft 30 and mainguidewire housing 32, respectively (i.e., at the distal end of thedistal segment 52 and the proximal end of the proximal segment 50).Typically, the length of the side inflation member 34 between theseproximal and distal connection points is such that prior to inflation ofthe main and side balloons 36, 34, there is relatively little slack orextra length in the side inflation member 34. While additionaladvantages are possible, minimizing the length of the side inflationmember between the proximal and distal connection points can help, forexample, minimize the profiles P3, P4, improve alignment of the lateralbranch opening with the side balloon during assembly of the catheterassembly 10 (e.g., crimping the stent 16 in place on the main balloon 36with the side balloon 38 aligned with the lateral branch opening 34),and reduce the incidence of loose material and structure at the distalend portion of the catheter assembly to improve ease of advancing thecatheter assembly 10 to a bifurcation treatment site.

Providing the side inflation member 34 with a minimum length between theproximal-most and distal-most connection points can result in additionaltension forces in the side inflation member generated when inflating themain balloon 36. Inflation of the main balloon 36 increases the lengthof the path that the side inflation member 34 must traverse between theproximal-most and distal-most connection points. These additionaltension forces in the side inflation member can be problematic. Forexample, the additional tension forces can weaken the connection betweenthe side inflation member segments 50, 52 and the side balloon 38,weaken the connection point at the proximal-most and distal-mostconnection points of the side inflation member 34 to the main guidewirehousing 32 at a point distal of the main balloon 36 and the cathetershaft 30 at a point proximal of the main balloon 36, create deformationsin the main balloon 38 outer profile, or create some misalignmentbetween the side balloon 38 and the lateral branch opening 84 of thestent 16.

Referring again to FIGS. 9 and 15, laterally offsetting the proximal anddistal segments 50, 52 in opposing directions relative to the centralproximal-distal line A of the side balloon 38 can result in a rotationalforce that rotate the side balloon 38 when the main balloon 36 isinflated and tension is generated along the length of the side inflationmember 34. This rotational force can slightly lengthen the sideinflation member or at least provide some flexibility in the sideinflation member 34 that can minimize the generation of the potentialtension induced concerns discussed above. The rotation effect can befurther magnified if the intersection point between the distal end 57 ofthe proximal segment is along the side 63 further around towards thedistal side 60 of the side balloon. Likewise, intersecting the proximalend 51 of the distal segment 52 with the balloon at a location furtheralong the side 61 of the balloon around towards the proximal side 62 ofthe balloon can create further rotation of the side balloon 38 andflexibility during inflation of the main and side balloons 36, 38 thatcan be advantageous.

FIGS. 20 and 21 illustrate an example mold used in creating a sideballoon 38 from the side inflation member 34. The mold 90 includes aproximal portion 92 and a distal portion 94 that together define aballoon cavity 96, a proximal segment cavity 98, and a distal segmentcavity 100. The mold 90 can be configured such that the balloon cavitydefines any desired balloon shape, size and orientation relative to theinflation member 34. The arrangement of the proximal and distal segmentcavities 98, 100 relative to the balloon cavity 96 results in a desiredlaterally offset intersection of one or more of the proximal and distalsegments 50, 52 of the side inflation member with the side balloon 38.

In operation, a side inflation member 38 is positioned within thecavities 96, 98, 100. Heat is applied to the mold 90 and pressure isapplied internal the side inflation member 34 that results in expansionof portions of the side inflation member 34 to fill the balloon cavity96. Typically, the mold is heated using an external source of heat suchas hot water or hot air. Pressure is applied internally in the sideinflation member 34 by filling the side inflation member 34 with a fluidsuch as heated water. The resulting wall thickness of the side balloon38 can be modified by, in addition to changing the size of the ballooncavity 96, increasing or reducing the thickness of portions of the sideinflation member 34 prior to the molding process. The thickness of theside inflation member 34 can also be reduced after the molding processto reduce the wall thickness of the balloon 38 (e.g., using grinding orother material removal techniques).

The two-part design of the mold 90 is advantageous for removing themolded product from the mold 90 since the side balloon 38 is now moldedintegral with the side inflation member 34 and would be difficult toremove otherwise. The mold 90 shape and two-piece configuration isexemplary only. Other configurations, such as molds having three or morepieces are possible in other examples.

FIGS. 22 and 23 illustrate a side balloon design that can help maintainthe side catheter branch 14 in a position oriented along the centralproximal-distal line A of the side balloon 38 during treatment of avessel bifurcation. The side balloon 138 includes an angled surface 66that extends from the proximal side 62 to the radially outward facingsurface 64. The angled surface 66 is generally planar in thisarrangement but can have other shapes and sizes in other arrangements.For example, the angled surface 66 can include a contoured shape portionsuch as a concave shaped portion. The angled surface 66 extendsgenerally at an angle β relative to a plane extending parallel with thecentral proximal-distal line A. Although alternatives are possible, theangle β is typically an acute angle (less than 90°) facing in a distaldirection. The angle β is typically in the range of about 15° to about90°, and preferably in the range of about 30° to about 75°.

The orientation of angled surface 66 relative to the side balloon 38 canbe altered depending on the orientation of the side balloon 38 relativeto the side inflation member 34 and the main balloon 36. For example, ifthe side balloon 38 extends radially away from the side inflation member34 and main balloon 36 at an angle less than 90° (e.g., in the range ofabout 30° to about (80°), the angle may be smaller while still providingthe desired function.

The angled surface 66 can have advantages related to keeping the sidecatheter branch 14 from moving laterally as the side balloon and mainballoon 38,36 inflate. Typically, the side balloon 38 can include agenerally cylindrical, spherical, hemispherical shape with manydifferent cross-sectional shapes possible. The side balloon 38 can alsotypically includes a rounded or convex shaped outward facing surface 64.Since many surfaces of such side balloon constructions are contoured ina convex direction, contact between the side catheter branch 14 and theside balloon 38 is usually a point (assuming no concave deformation ofthe side catheter branch 14 and side balloon 38). This type of minimumcontact on a convex surface can make it more difficult to maintain asingle position of the side catheter branch aligned along the centralproximal-distal line A of the side balloon 38. Including the generallyplanar angled surface 66 along the proximal side 62 provides a moresubstantial contact surface between the side catheter branch 14 and theside balloon 38. Further, lack of curvature across the width of thesurface 66 can make it easier to maintain alignment of the side catheterbranch 14 along the central proximal-distal line A.

The addition of other structure such as convex portions, protrusions, ormultiple planar surfaces in addition to or in place of the angledsurface 66 can provide the same or similar effect of helping maintainalignment of the side catheter branch 14 with the centralproximal-distal line A.

The catheter assembly 10 described above with reference to FIGS. 1-7 canbe used for treatment of a vessel bifurcation 22 as shown in FIGS.24-26. Typically, a main vessel guidewire 18 is first inserted into amain vessel 24 of the vessel bifurcation 22 to a point distal of thevessel bifurcation. A branch vessel guidewire 20 is advanced to thevessel bifurcation and inserted through an ostium or opening 28 of abranch vessel 26. Proximal ends of the guidewires 18, 22 are theninserted into the main guidewire lumen 46 and branch guidewire lumen 72,respectively. The catheter assembly 10 is advanced over the guidewires18, 22 to the vessel bifurcation as shown in FIG. 24. The catheterassembly 10 is advanced further distally until the distal end portion 70of the side catheter branch 14 is positioned within the branch vessel26. A marker system can be used to help confirm proper rotational(radial) and axial alignment of the lateral branch opening 84 of thestent 16 relative to the ostium 28 into the branch vessel 26. An examplemarker system is described below.

After proper axial and rotational positioning of the catheter assembly10 is confirmed, the main and branch balloons 36, 38 are inflated. Thelaterally offset orientation of at least the proximal segment 50 of theside inflation member 34 provides for positioning of the side catheterbranch 14 aligned with the central proximal-distal line A of the sideballoon 38 prior to and during inflation of the balloons 36, 38. Centralalignment of the side catheter branch 14 with the side balloon 38 canimprove consistency in aligning the lateral branch opening 84 with theostium 28 of the vessel bifurcation. Typically, inflation of the sideballoon 38 can also result in expansion of expandable structure 86surrounding the lateral branch opening 84. The expanded expandablestructure 86 can extend through the ostium 28 and at least partiallyinto the branch vessel 26.

In a follow-up step, after the balloons 36, 38 have been deflated andthe catheter branches 12, 14 retracted proximally, a separate balloonmember (not shown) can be advanced through the lateral branch opening totreat the branch vessel 26 and further open the expandable structure 86into the branch vessel 26. In a still further step, an additional branchstent can be advanced through the lateral branch opening 84 and into thebranch vessel and expanded to treat further the branch vessel 26.

The particular method steps described above can be altered in otherexample treatment methods. For example, one of the guidewires 18, 20 canbe advanced with the catheter assembly 10 to the vessel bifurcation. Inanother example, the balloons 36, 38 can be inflated sequentially ratherthan simultaneously for purposes of, for example, improving alignment ofthe lateral branch opening 84 with the ostium into the branch vessel.

A wide variety of stents, catheters, and guidewire configurations can beused with the catheter assembly embodiments of the present disclosure.The inventive principles disclosed herein should not be limited to anyparticular design or configuration. Some example stents that can be usedwith the catheter assemblies disclosed herein can be found in, forexample, U.S. Pat. Nos. 6,210,429; 6,325,826; 6,706,062; and 7,220,275,and U.S. Published Patent Application No. 2004/0176837 titledSELF-EXPANDING STENT AND CATHETER ASSEMBLY AND METHOD FOR TREATINGBIFURCATIONS, the entire contents of which are incorporated herein byreference. In general, the aforementioned stents include a lateralbranch opening located between distal and proximal open ends of thestent. The lateral branch opening defines a path between an inner lumenor inner volume of the stent and an area outside of the stent. The stentlateral branch opening is distinct from the cell openings definedbetween strut structures from which the stent sidewall is constructed.In some stents, the lateral branch opening can be surrounded byexpandable structure. The expandable structure can be configured toextend radially into the branch lumen of the bifurcation upon expansionof, for example, an inflatable portion of the bifurcation treatmentsystem. Typically, the stent is expanded after being positioned in themain lumen with the lateral branch opening aligned with an opening intothe branch lumen. Alignment of the lateral branch opening with theopening into the branch lumen includes both radial and axial alignment.The stent, including the expandable structure surrounding the lateralbranch opening, can be expanded with a single expansion or multipleexpansions using one or more inflatable members.

The main and side balloons, and all other balloons disclosed herein, canbe made of any suitable balloon material including compliant andnon-compliant materials and combinations thereof. Some example materialsfor the balloons and catheters disclosed herein include thermoplasticpolymers, polyethylene (high density, low density, intermediate density,linear low density), various copolymers and blends of polyethylene,ionomers, polyesters, polycarbonates, polyamides, poly-vinyl chloride,acrylonitrile-butadiene-styrene copolymers, polyether-polyestercopolymers, and polyetherpolyamide copolymers. One suitable material isSurlyn®, a copolymer polyolefin material (DuPont de Nemours, Wilmington,Del.). Still further suitable materials include thermoplastic polymersand thermoset polymeric materials, poly(ethylene terephthalate)(commonly referred to as PET), thermoplastic polyamide, polyphenylenesulfides, polypropylene. Some other example materials includepolyurethanes and block copolymers, such as polyamide-polyether blockcopolymers or amide-tetramethylene glycol copolymers. Additionalexamples include the PEBAX® (a polyamide/polyether/polyester blockcopolymer) family of polymers, e.g., PEBAX®70D, 72D, 2533, 5533, 6333,7033, or 7233 (available from Elf AtoChem, Philadelphia, Pa.). Otherexamples include nylons, such as aliphatic nylons, for example, VestamidL21011F, Nylon 11 (Elf Atochem), Nylon 6 (Allied Signal), Nylon 6/10(BASF), Nylon 6/12 (Ashley Polymers), or Nylon 12. Additional examplesof nylons include aromatic nylons, such as Grivory (EMS) and NylonMXD-6. Other nylons and/or combinations of nylons can also be used.Still further examples include polybutylene terephthalate (PBT), such asCELANEX® (available from Ticona, Summit, N.J.), polyester/ether blockcopolymers such as ARNITEL® (available from DSM, Erionspilla, Ind.),e.g., ARNITEL® EM740, aromatic amides such as Trogamid (PA6-3-T,Degussa), and thermoplastic elastomers such as HYTREL® (Dupont deNemours, Wilmington, Del). In some embodiments, the PEBAX®, HYTREL®, andARNITEL® materials have a Shore D hardness of about 45D to about 82D.The balloon materials can be used pure or as blends. For example, ablend may include a PBT and one or more PBT thermoplastic elastomers,such as RITEFLEX® (available from Ticona), ARNITEL®, or HYTREL®, orpolyethylene terephthalate (PET) and a thermoplastic elastomer, such asa PBT thermoplastic elastomer. Additional examples of balloon materialcan be found in U.S. Pat. No. 6,146,356, which is incorporated herein byreference.

The catheter assembly 10 can include marker material that is visibleunder X-ray or in fluoroscopy procedures. FIG. 2 illustrates markers 1-4positioned along the distal end portions of the main and side catheterbranches 12, 14. Any features of the system 10 that include markermaterial can be more easily identified and distinguished under X-ray orin fluoroscopy procedures. Some example marker materials include gold,platinum and tungsten. In one embodiment, the marker material can beincluded in a band structure that is secured to at least one of the mainand side catheter branches 12, 14. In other embodiments, the markermaterial is part of the material composition of portions of the main andside catheter branches 12, 14. Viewability of features of the catheterassembly 10 under X-ray or fluoroscopy can assist the physicianoperating the system 10 to more easily adjust a position of the system10 relative to the vessel bifurcation 40. Example markers and markermaterials suitable for use with system 10 are described in U.S. Pat. No.6,692,483 to Vardi, et al., and co-pending U.S. Published PatentApplication No. 2007/0203562, filed on Feb. 22, 2007, and titled MARKERARRANGEMENT FOR BIFURCATION CATHETER, which matters are incorporatedherein by reference.

Alternative catheter assemblies to those described above are configuredfor use with stents having self-expanding features. Self-expandingstents and self-expanding features of a stent typically do not requirethe use of an inflatable member such as a balloon to expand the sent orstent feature. Typically, self-expanding stents, such as those stentsdescribed in U.S. Published Patent Application No. 2004/0176837, areheld in a constricted state using a sheath that fits over the stent. Inthe constricted state, the stent is able to navigate through a bodylumen to the treatment site. Once the stent and sheath are positioned atthe treatment site, the sheath is retracted proximally to release thestent for expansion of the stent into a radially expanded state.

One aspect of the present disclosure relates to a catheter assembly thatincludes a stent, a main catheter branch, and a side catheter branch.The stent includes a proximal open end, a distal open end, and a lateralbranch opening. The main catheter branch includes a proximal end portionand a distal end portion. The distal end portion includes a mainballoon, a side balloon, and a side inflation lumen. The main balloonincludes a proximal end portion, a distal end portion, and alongitudinal dimension extending between the proximal and distal endportions. The side balloon is arranged at a location between theproximal and distal end portions of the main balloon and in alignmentwith the lateral branch opening of the stent. The side balloon isconfigured to extend radially outward relative to the main balloon whenthe side balloon is inflated, and defines a central proximal-distalline. The side inflation member intersects the side balloon at alocation offset laterally from the side balloon central proximal-distalline. The side catheter branch defines a branch guidewire lumen andextends through the lateral branch opening of the stent. The sidecatheter branch is centrally aligned with the side balloon centralproximal-distal line.

Another aspect of the present disclosure relates to a catheter assemblythat includes a main balloon, a side balloon, and a side inflationmember. The main balloon includes a proximal end portion, a distal endportion, and a longitudinal dimension extending from the proximal endportion to the distal end portion. The side balloon is positioned at alocation between the proximal and distal end portions of the mainballoon and is configured to extend radially outward relative to themain balloon when the side balloon is inflated. The side balloon has aproximal-most point, a distal-most point, and a in centralproximal-distal line that extends from the proximal-most point to thedistal-most point of the side balloon. The side inflation memberintersects the side balloon at a location offset laterally from the sideballoon central proximal-distal axis.

A still further aspect of the present disclosure relates to a method ofassembling a stent delivery system. The stent delivery system includes astent, a main catheter branch, and a side catheter branch. The stent hasa proximal open end, a distal open end, and a lateral branch opening.The main catheter branch includes a main balloon, a side balloon and aside inflation member, wherein the side balloon defines a centralproximal-distal line, and the side inflation member intersects the sideballoon at a location offset laterally from the side balloon centralproximal-distal line. The side catheter branch defines a branchguidewire lumen. Steps of the method include extending the main catheterbranch into the stent with the main balloon and the side balloonpositioned in the stent and the side balloon aligned with the lateralbranch opening of the stent, extending the side catheter branch into thestent with a portion of the side catheter branch extending through thelater branch opening of the stent and the side catheter branch centrallyaligned with the side balloon central proximal-distal line, and crimpingthe stent into releasable engagement with the main catheter branch andthe side catheter branch.

It is noted that not all of the features characterized herein need to beincorporated within a given arrangement, for the arrangement to includeimprovements according to the present disclosure.

What we claim is:
 1. A catheter assembly, comprising: (a) a stent havinga proximal open end, a distal open end, and a lateral branch opening;(b) a main catheter branch having a proximal end portion and a distalend portion, the distal end portion including: i. a main balloon, themain balloon having a proximal end portion, a distal end portion, and alongitudinal axis extending between the proximal and distal endportions; ii. a side balloon arranged at a location between the proximaland distal end portions of the main balloon and in alignment with thelateral branch opening of the stent, the side balloon configured toextend radially outward relative to the main balloon when the sideballoon is inflated, the side balloon defining a central proximal-distalline; iii. a side inflation member including proximal and distalsegments that intersect the side balloon at locations offset laterallyfrom the side balloon central proximal-distal line, wherein the proximaland distal segments are laterally offset in opposing directions relativeto the central proximal-distal line; and (c) a side catheter branchdefining a branch guidewire lumen, the side catheter branch extendingthrough the lateral branch opening of the stent, the side catheterbranch being centrally aligned with the side balloon centralproximal-distal line.
 2. The assembly of claim 1, wherein the proximalsegment extends from the side balloon in a proximal direction on oneside of the central proximal-distal line, and the distal segment extendsfrom the side balloon in a distal direction on the opposite side of thecentral proximal-distal line.
 3. The assembly of claim 1, wherein themain catheter branch further includes: (a) a catheter shaft having adistal end portion and defining a main inflation lumen; and (b) a mainguidewire housing defining a main guidewire lumen, the main guidewirehousing extending through at least a portion of the main inflation lumenand through the main balloon from the proximal end portion to the distalend portion of the main balloon.
 4. The assembly of claim 1, wherein atransverse line extending through the side balloon perpendicular to thecentral proximal-distal line intersects the side balloon at first andsecond side points, wherein the proximal segment intersects the sideballoon at a location closer to the first side point than theproximal-most point, and the distal segment intersects the side balloonat a location closer to the second side point than the distal-mostpoint.
 5. The assembly of claim 1, wherein the side balloon centralproximal-distal line divides the side balloon in half in a projectionview of the side balloon.
 6. The assembly of claim 1, wherein theproximal and distal segments are connected to the side balloon such thatupon inflation of the main balloon, the side balloon rotates, therebylengthening the side inflation member.
 7. The assembly of claim 1,wherein the central proximal-distal line is parallel to the main balloonlongitudinal axis.
 8. A method of assembling a stent delivery system,the stent delivery system including a stent, a main catheter branch, anda side catheter branch, the stent having a proximal open end, a distalopen end, and a lateral branch opening, the main catheter branchincluding a main balloon, a side balloon and a side inflation member,the side balloon defining a central proximal-distal line, and the sideinflation member including proximal and distal segments that intersectthe side balloon at locations offset laterally from the side ballooncentral proximal-distal line, wherein the proximal and distal segmentsare laterally offset in opposing directions relative to the centralproximal-distal line, the side catheter branch defining a branchguidewire lumen, the method comprising: (a) extending the main catheterbranch into the stent with the main balloon and the side balloonpositioned in the stent and the side balloon aligned with the lateralbranch opening of the stent; (b) extending the side catheter branch intothe stent with a portion of the side catheter branch extending throughthe lateral branch opening of the stent and the side catheter branchcentrally aligned with the side balloon central proximal-distal line;and (c) crimping the stent into releasable engagement with the maincatheter branch and the side catheter branch.
 9. The method of claim 8,wherein the proximal segment extends proximally from the side balloonand the distal segment extends distally from the side balloon, andextending the side catheter branch into the stent includes positioningthe side catheter branch between the proximal and distal segments of theside inflation member.
 10. The method of claim 8, wherein crimping thestent includes reducing an outer profile of the stent while maintainingthe side balloon in alignment with the lateral branch opening and whilemaintaining the side catheter branch centrally aligned with the sideballoon central proximal-distal line.